Field of the Invention
The present invention relates to a recording apparatus that records an image by ejecting liquid droplets toward a recording medium, and also relates to a recording method and a liquid ejection head.
Description of the Related Art
The size of liquid droplets ejected from ink ejection ports of a liquid ejection head included in a recording apparatus has been reduced to increase the quality of an image recorded on a recording medium. Also, to increase the image recording speed, the number of ejection ports has been increased by increasing the density of the ejection ports, and the ink ejection frequency has been increased.
When the quality of the recorded image and the recording speed are increased in the above-described way, as illustrated in FIG. 15A, vortices A may be generated between a liquid ejection head H and a recording medium W. The vortices A are generated between the liquid ejection head H and the recording medium W as a result of interference between the airflows due to the ejection of liquid droplets ID from ink ejection ports H1 of the liquid ejection head H and the airflows due to the relative movement between the liquid ejection head H and the recording medium W. Referring to FIG. 15A, the recording medium W moves in the direction of arrow x2 relative to the liquid ejection head H, and the vortices A are generated in regions at the front side in the direction of the relative movement of the liquid ejection head H (left side in FIG. 15A). The vortices A are generated at similar regions also when the liquid ejection head H is moved in the direction of arrow x1 relative to the recording medium W.
When the vortices A are generated between the liquid ejection head H and the recording medium W as described above, there is a risk that the positions at which the liquid droplets P are applied to the recording medium W will be displaced and the quality of the recorded image will be reduced.
Referring to FIG. 15C, U.S. Pat. No. 6,997,538 describes a method of ejecting air from an outlet N toward the space between the liquid ejection head H and the recording medium W to eliminate the vortices between the liquid, ejection head H and the recording medium W.
However, to reduce airflow turbulence by ejecting air as illustrated in FIG. 15C, a large amount of air relative to the flow rate of air that enters the space between the liquid ejection head H and the recording medium W needs to be ejected from the outlet N during a recording operation. Moreover, there is a risk that, due to the flow of the large amount of air that is ejected, the positions at which the liquid droplets D are applied will be displaced by a large distance and the quality of the recorded image will be reduced.
The inventors of the present invention have found that, when the ejection ports are densely arranged in the liquid ejection head or when the ejection frequency is relatively high, there is a risk that the stability of the vortices formed between the liquid ejection head and the recording medium will be reduced. The inventors have also found that the unstable vortices may cause displacements of the positions at which satellite droplets are applied, which leads the formation of patterns similar to the wind patterns on the sand and a reduction in the image quality.
The present invention provides a liquid ejection head, a recording apparatus, and a recording method with which vortices that affect the accuracy of the positions at which liquid droplets are applied can be stabilized so that airflow turbulence can be efficiently suppressed and high-quality images can be recorded.